Typically, wheeled tool bars are connected to tractor-pulled wheel farm implements by mechanisms which space the tool bar rearwardly of the wheeled implement and generally parallel to the backside thereof. For example, the wheeled implement may be a transportable seed and/or fertilizer storage hopper for supplying seed and/or fertilizer to a pneumatic-transport distribution system. Further, the tool bar may carry a plurality of soil-engaging ground tools which receive the seed and/or fertilizer from the distribution system and deposit the same into the ground in a conventional manner.
In particular, however, only the wheeled implement (i.e. the transportable storage hopper) immediately behind the tractor is free to pivot as the tractor makes a turn. That is, additional wheeled implements which are spaced behind the wheeled storage hopper implement do not pivot laterally relative thereto.
Conventional tool bars, which are typically mounted behind wheeled storage hopper implements, are currently rather elongated and generally carry a plurality of soil-engaging ground tools thereon, for engaging the soil as mentioned above. Further, the conventional tool bar typically includes means for lowering and raising the tool bar relative to the ground, for thereby causing the ground tools to engage the soil or to be spaced above the soil, respectively. Because of the fixed orientation of the tool bar relative to the wheeled implement backside in conventional agricultural implements, the tool bar and cart wheels can be caused to skid uncontrollably in a direction which is transverse to the path of tractor movement as the tractor makes a turn.
For example, as the tractor makes a turn to the left, which causes the tractor-connected end of the wheeled storage hopper implement to pivot relative to the tractor and accordingly be pulled to the left, the fixed relationship of the wheeled tool bar relative to the wheeled storage hopper implement backside causes the storage hopper implement wheels to uncontrollably side skid to the left and the tool bar wheels to side skid either to the right or to the left depending on whether the ground tools are raised or lowered, respectively. Side skidding of the cart and tool bar wheels usually causes undesirable ruts to form in the field transverse to the path of tractor movement. When the ground tools have been lowered to their above-mentioned soil-engaging (i.e. so-called "working") position, it can be appreciated that the degree of undesired side rutting is even greater. For example, as the tractor moves through the field, the plurality of soil-engaging ground tools are used to form a like plurality of spaced apart furrows in the soil for planting seed, fertilizing crops, etc. Side rutting is thus undesirable because it interferes with furrow formation. The degree of side rutting may even be great enough to destroy freshly planted seed and/or render ineffective (i.e. because the depth below the soil has been altered) freshly deposited fertilizer.
Simply providing the tool bar with a conventional pivotal connection which permits lateral pivoting of the tool bar relative to the wheeled implement backside as the tractor causes the wheeled storage hopper implement to move through a turn introduces other problems, however. That is, while initially solving the above-mentioned tool-bar and cart side-skidding problem, the conventionally pivotable connection introduces other side-skidding problems and a number of problems of other sorts. For example, the conventional laterally pivotable connection allows the tool bar to sway transverse to the path of movement whenever the tool bar wheels are not precisely lined up behind the implement wheels. Further, conventional laterally pivotable connections unduely complicate backup of the wheeled implement when the wheeled tool bar is connected thereto. Operation on steep hillsides further causes complications when the tool bar drifts sideways relative to movement of the wheeled storage hopper implement or so-called "cart" and/or tractor.